import numpy as np
import cv2 as cv

# 创建一张图片
img = np.ones((512,512,3), np.uint8)*255

# 画圆
center  = (round(img.shape[1]/2),round(img.shape[0]/4))
radius  = 87
color   = (0,255,0)
thinknessPx = -1
cv.circle(img, center,radius, color, thinknessPx)

cv.imshow("img", img)
cv.waitKey(0)
cv.destroyAllWindows()